Metacarpophalangeal joints (MCP)

• Joint Classification:

  • Synovial condyloid joints
• Axis of movement

  • Transverse and AP
• Articular Surfaces:

  • Rounded head of metacarpal (convex)

  • Base of proximal phalanx (concave)

  • Both covered in hyaline cartilage

  • Fibro-cartilaginous plate present known as palmar ligament (increases articular area of base of proximal phalanx)
• Joint Capsule:

  • Loose fibrous capsule

  • Attached to articular margins

  • Strengthened laterally by collateral ligaments
• Ligaments:

  Palmar ligament:

  • Fibro-cartilaginous plate

  • Role: Increasing surface area of proximal phalanx, limit extension.
• Ligaments:

  Collateral ligaments:

  • Sides of MC head to palmar side base proximal phalanx

  • Role: Stabilise joint (tension increases during flexion)
• Ligaments:

  Deep transverse metacarpal ligaments:

  • Connect four palmar ligaments of 2nd to 5th MCP joints

  • Role: Acting to bind heads of MCP’s together (Limit abduction)
• Movements:

  • Flexion: >90 ° (increasing towards the little finger)

  • Extension: up to 50 °

  • Abduction and adduction: 30 °(when MCPs positioned in extension)